This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Microvascular hyperpermeability is a hallmark of inflammation associated with hemorrhagic shock. Despite the fact that alcohol intoxication contributes to one-third of accidental deaths and that nearly 50% of emergency room patients have positive blood alcohol concentrations, there have been no studies of how alcohol intoxication affects normal microvascular exchange or microvascular leak caused by trauma or inflammation in vivo. A better understanding of how the microcirculation functionally adapts to alcohol intoxication is needed to improve strategies for resuscitation and prevention of edema, uncontrolled inflammation, and infection. Studies from our laboratory have shown that the cytoskeleton and adherens junctions between endothelial cells play important roles in both the maintenance of normal barrier function and as effectors of the hyperpermeability response during systemic inflammation. Our preliminary data show that acute alcohol exposure disrupts the endothelial actin cytoskeleton and intercellular junctions. We have also observed that alcohol administration exacerbates the in vivo hyperpermeability reaction to inflammatory stimuli. These events appear to involve oxidative stress at both the systemic and local (endothelial cell) level. Thus, we hypothesize that alcohol exacerbates hemorrhagic shock-induced microvascular leakage by causing oxidative stress-mediated cytoskeletal rearrangement in endothelial cells, weakening junctions and creating an exaggerated response to inflammatory stimuli. To intermediate specific aims to test this hypothesis will be to: 1) characterize microvascular barrier abnormalities during combined acute alcohol intoxication and hemorrhagic shock, which will provide in vivo data not currently available, 2) test the role of alcohol-induced oxidative stress during combined alcohol intoxication and hemorrhagic shock, and 3) examine the role of endothelial cytoskeletal disruption in microvascular barrier dysfunction during combined alcohol intoxication and hemorrhage. These intermediate aims will be addressed using a fixed pressure hemorrhage model combined with acute alcohol administration. An integrated approach utilizing in vivo intravital microscopy of the mesenteric microcirculation, an established isolated perfused venule technique, and molecular biology methods will be used to successfully complete this study. The data obtained from this study will provide new insights into the mechanisms underlying microvascular leakage during shock. The ultimate goal of these studies is to promote development of better resuscitation methods for shock patients.